Chlorinated benzenes emission

Chlorinated Hydrocarbons. In the magnesium plant, samples from two different locations have been analyzed. Emissions from the chlorination plant were scrubbed with seawater and the particles collected as sewage. Figure 2 shows a chromatogram of chlorinated hydrocarbons in a sewage sample. As revealed by the chromatogram, the sewage contains a number of chlorinated benzenes and styrenes. 

The environmental effects from the emission of these chlorinated benzenes are estimated to be insigificant because of the low levels and the further dilution by factors of 103 to 105 in the atmosphere before any hunan or plant exposure. 

Further chlorinated compounds detected in Lippe river sediments could not be attributed clearly to distinct emission sources. Within the group of chlorinated benzenes, tri-, tetra- and pentachlorinated isomers did not show siginicant distribution patterns. In contrast, samples from the upper areas (sampling locations 8 and 9) were significantly less contaminated by dichlorobenzenes. Among other applications dichlorobenzenes are ingredients of toilet cleaners. Therefore, their distribution pattern in Lippe river sediments may reflect partially the pollution from municipal effluents. 

Chlorinated benzenes are key precursors for the industrial production of colours, pesticides, rubber products and disinfectants. Additionally, hexachlorobenzene (HCB) was used for a long time as a pesticide. Octachlorostyrene is a specific by-product of the production of magnesium, as well as a by-product of the technical production of chlorine (Kaminski and Hites, 1984). Hexachloro-1,3-butadiene is used in the rubber production, as hydraulic liquid, solvent and as a by-product of the technical synthesis of chlorinated compounds like tetrachloroethene (Booker and Pavlostathis, 2000). Bis(chloropropyl)ethers represent byproducts of the technical synthesis of epichlorhydrin, used for the production of epoxy resins and disinfectants. The concentration profile of the individual chlorinated compounds reveals different emission histories. 

For the chlorinated benzenes, a very similar distribution within the sediment core is observed as for some PAHs, e.g. benzo[a]pyrene. An elevated large-scale industrial activity related to these compounds can be deduced for the time between 1947 and 1955. We attribute the decrease in contamination towards the top layers to a reduction of emissions as a result of more efficient sewage treatment plants (Fig. 1A,B) as well as a modified array of products. The concentration profile of HCB (Fig. 6C) and all lower chlorinated benzenes (Tab. 2) suggests the dominance of industrial sources responsible for the contamination as contrasted to agricultural emission derived from pesticide usage. It should be noted that the contamination level of 1,4-dichlorobenzene was elevated in the time period between 1975 and 1980, comparable with concentration levels determined in Rhine river sediments 1982/83. The extensive use of 1,4-dichlorobenzene as an odorous ingredient of toilet cleaners contributed additionally to the contamination via sewage effluents (LWA, 1987/1989). 

The pyrolysis of vinylidene chloride produced a range of chlorinated aromatic compounds including polychlorinated benzenes, styrenes, and naphthalenes (Yasahura and Morita 1988), and a series of chlorinated acids including chlorobenzoic acids has been identified in emissions from a municipal incinerator (Mowrer and Nordin 1987). 

Further specific studies have used diffusive samplers to investigate the impact of emissions from cars kept in an integral garage on benzene concentrations in the indoor air (Mann, Crump and Brown, 2001) and to assess the effectiveness of remedial measures used to reduce radon ingress into homes for controlling ingress of chlorinated butadienes present in contaminated land (Crump et al., 2004). 

One of the major uses of activated carbon is in the recovery of solvents from industrial process effluents. Dry cleaning, paints, adhesives, polymer manufacturing, and printing are some examples. Since, as a result of the highly volatile character of many solvents, they cannot be emitted directly into the atmosphere. Typical solvents recovered by active carbon are acetone, benzene, ethanol, ethyl ether, pentane, methylene chloride, tetrahydrofuran, toluene, xylene, chlorinated hydrocarbons, and other aromatic compounds [78], Besides, automotive emissions make a large contribution to urban and global air pollution. Some VOCs and other air contaminants are emitted by automobiles through the exhaust system and also by the fuel system, and activated carbons are used to control these emissions [77,78],... 

MWP. However, the quantity of chlorinated hydrocarbons during MWP degradation was higher than 3P/PVC/PET and 3P/PVC degradation liquid products. Gas chromatography equipped with an atomic emission detector (GC-AED), was used for selective detection of Cl in the liquid products. As can be seen from Figure 18.19, the presence of PET produced the additional chlorinated hydrocarbons than 3P/PVC. The liquid products were analyzed by GC-MS to identify the compounds. The presence of chlorinated compounds with model and MWP were observed as 2-chloro-2-phenyl propane, 2-chloro-2-methyl propane, 2-chloro-2-methyl pentane, and a-chloro ethyl benzene. 

After PCDEs were detected in a fly ash from a municipal waste incinerator in Finland [36], the occurrence of PCDEs in combustion wastes has not been studied much. PCDEs could be formed during incomplete combustion by condensation from chlorophenols as has been indicated for PCDDs [54], but de novo synthesis is also possible [55]. The formation of chlorinated compounds is always possible during combustion in the presence of organic material and chloride. The formation of PCDEs de novo in combustion has been described in the literature review of Kurz s thesis [4]. Briefly, diphenyl can be formed from the phenoxy radical and benzene which in turn can be formed from alkene radicals. If the formed molecule does not already contain chlorine, chlorination of diphenyl ether can occur, e.g., in the presence of HCl. It has been suggested, however, that PCDEs, in contrast to PCDDs and PCDFs, are not formed to a great extent de novo on solid surfaces or in the gas phase in thermal processes during metal reclamation processes [56]. When PCDEs were analyzed in emission samples of a metal reclamation plant in Finland, all PCDEs were below 4 ng nr3. 

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